How New York Cut Prison Rolls and Crime at the Same Time

How did New York State manage to cut its prison population while reducing crime? Send many fewer drug offenders to prison and have many more minor offenders serving shorter sentences, experts told a “smart justice” symposium yesterday near Washington, D.C. The session was sponsored by the CNA consulting firm in Alexandria, Va., which is working with the U.S. Bureau of Justice Assistance on a “smart policing” initiative.

The New York experience bolsters the growing evidence against the lazy assumption that reducing the number of people sent to prison will yield an increase in crime (or the converse, that sending more people to prison will yield a decrease in crime). In the past 20 years or so, crime has declined almost everywhere in the U.S., both in states that have been increasing their prison populations and states that have been reducing their prison populations. Since 1999, Kansas, Michigan, New Jersey, and New York have reduced their prison populations by 5-20%, with no increase in crime.

Of course, there’s no way to do a perfectly controlled experiment. But economists can use modeling to estimate the extent to which one factor influences another. At a panel talk I recently attended at Stanford, Berkeley economist Stephen Raphael shared his estimate that only about 20% of the crime drop of recent years can be attributed to higher rates of imprisonment. Freakonomics economist Steven Levitt’s estimate is about 25% (PDF p. 4). As the Sentencing Project has concluded (PDF p. 8):

While incarceration is one factor affecting crime rates, its impact is more modest than many proponents suggest, and is increasingly subject to diminishing returns. Increasing incarceration while ignoring more effective approaches will impose a heavy burden upon courts, corrections and communities, while providing a marginal impact on crime. Policymakers should assess these dynamics and adopt balanced crime control policies that provide appropriate resources and support for programming, treatment, and community support.